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FSR ? more muscle = no news for ya!

For the average SuppVersity reader the sentence "Acute Post-Exercise Myofibrillar Protein Synthesis Is Not Correlated with Resistance Training-Induced Muscle Hypertrophy in Young Men" is not just the title of a recent paper in the open access journal PLOS|ONE, its also the experimental verification of a claim Ive made in almost all my articles about the acute effects of certain training modalities and/or supplements on myofibrillar protein synthesis and the corresponding increases in muscle size some people appear to expect from a 2h-long 10% increase in fractional protein synthesis (learn more).

And yes, practically speaking these findings imply that we have to question the real world significance of all the neat studies on the "superior muscle building effects" of whey protein, BCAAs and even more so leucine, in which the authors base their recommendations on acute increases in post-exercise protein synthesis.
In the corresponding experiment that was funded by the National Science and Engineering Research Council (NSERC) of Canada Cameron J. Mitchell et al. determined whether the acute myofibrillar protein synthesis measured acutely in training-naive subjects after their first bout of resistance exercise with protein consumption would correlate with the actual increase in muscle size after 16 weeks of resistance training.

Suggested read: "Protein Intake & Muscle Catabolism: Fasting Gnaws on Your Muscle Tissue and Abundance Causes Wastefulness " | more

Before the actual experiment began, the subjects, healthy young recreationally active normal-weight men (177 cm; body mass index = 26.4 kg/m²; men age 22 years) without previous strength training experience, underwent a magnetic resonance imagining (MRI) scans of their right thigh to determine muscle volume, a dual, energy x-ray absorptiometry (DXA) scan to assess whole body fat and bone-free mass (lean mass) and standardized strength tests to determine their maximal isotonic strength (often labeled the 1RM) for all training exercises.

After all baseline measurements (including baseline muscle protein synthesis) were recorded, the subjects completed 16 weeks of RT while ingesting a protein rich beverage (30g of the same whey protein of which Burd et al. showed in 2012 that it elicits a higher increase in MPS than casein) immediately after their exercise session and with breakfast on non-training days.

"Briefly, participants trained four times weekly with two upper and two lower body workouts. Lower body exercises are described above in the acute exercise session. Upper body exercises consisted of chest press, shoulder press, seated row, lat pulldown, bicep curl and tricep extension. The program was progressive in linear manner moving from 3 sets of 12 repetitions to 4 sets of 6  repetitions. At the end of the training period, MRI, DXA scans and strength testing were repeated." (Mitchell. 2014)

If you look at the above description of the workout (and supplementation regimen) you will probably agree that this is pretty much what the majority of resistance physique oriented gym-goers do.

Figure 1: Myofibrillar fractional protein synthesis rate (left) measured acutely after a single workout and changes in muscle volume (%) over the whole 16-week study period as a function of the 1-6h post-workout FSR (Mitchell. 2014).

People who hope that the often reported increases in fractional protein synthesis would pay off and yield increased net muscle gains and thus exactly what Mitchell et al. did not observe in their study, which could not establish the corresponding correlation between the actute increase in post-workout fractional protein synthesis (Figure 1, left) and the chronic change in muscle volume (Figure 1, right).

Figure 2: Changes in muscle volume (%) expressed relative to acute increases in 4E-BP (Mitchell. 2014).

If anything, it was the expression of the Eukaryotic translation initiation factor 4E-binding protein 1 aka 4E-BP1 one of the motors of protein synthesis, but not the increase in myofibrillar fractional protein synthesis that looked as if it could have any predictive value with respect to the increase in muscle volume, the young men experienced in the course of the 16-week training period.

After thinking about the implications of these findings for a minute, I do yet have to admit that the assumption that this would refute the previously invoked recommendations completely, is probably premature.
Reference:

• Burd, Nicholas A., et al. "Greater stimulation of myofibrillar protein synthesis with ingestion of whey protein isolate v. micellar casein at rest and after resistance exercise in elderly men." British Journal of Nutrition 108.06 (2012): 958-962.

Its obviously to have the 24h effects on testosterone and cortisol than only those measured after the workout , but can we make solid conclusions based on the additional data?

In spite of the fact that the acute testosterone and cortisol response to exercise appears to have little direct effects on the overall training outcome (Schoenfeld. 2013), acute increase in cortisol and reductions in testosterone, i.e. a decrease in the testosterone:cortisol ratio is a classic feature of overtraining and can very well blunt, if not reverse the beneficial effects of exercise on your health and body composition.

Against that background a recent experiment that was conducted by researchers from the University of Chieti-Pescara in Italy could be of great interest to everyone who is performing high intensity interval training on a regular basis. Why?

Well, in contrast to previous studies, Blasio et al. investigated both the acute and 24h effects of a high intensity interval resistance training regimen in trained young men.
To characterize the effects on heart rate and hormonal responses the subjects, eight trained, healthy trained men (28.61 ±3.51 yrs), performed three different workouts which had the same exercises, the same load and number of repetitions for each exercise, but different exercise order, recovery and speed of execution.

• RANDOM workout: the assigned goal was to complete the assigned repetitions respecting only two duties. The first one was don’t stop until all of the repetitions were completed; the second was that there were no assigned order of execution of exercises and no assigned consecutive repetitions to complete.
  
  Participants were thus free to choose both the order of exercises and number of consecutive repetitions for each exercise (i.e. 2 repetitions of kettlebell swing, 10 repetitions of medicine ball slam, 20 repetitions of squat, 4 repetitions of spin with Bulgarian bag, etc.).
  
  No recovery period was assigned, except the time necessary to move from a station to another, and no speed of execution of exercises was assigned: participants were free to choose the preferred speed. 
• LADDER workout: respecting the following order of execution, kettlebell swing, medicine ball slam, spin with Bulgarian bag, squat, pull-up, burpee, participants had to complete the total repetitions according to a pyramidal scheme (e.g. 1st lap 10 repetitions at each exercise, 2nd lap 9 repetitions at each exercise) until the total number of repetitions of each exercise was executed.
  
  Each lap of the circuit was followed by 1 minute of recovery. No speed of execution of exercises was assigned: participants were free to choose the preferred speed. 
• AS SOON AS POSSIBLE (ASAP) workout : respecting the following order of execution, kettlebel swing, medicine ball slam, spin with Bulgarian bag, squat, pull-up, burpee, participants had to complete the total volume in six laps executed as soon as possible.
  
  During each lap participants had to complete the sixth part of total number of repetitions of each exercise without rest among exercises. Each lap of the circuit was followed by 1 minute of recovery.

Salivary samples were collected before and after each workout, at 11:00 p.m. and at 7:00 a.m. of the following day. Salive was also collected during a non-training day. Similarly, before and after the workout, plasma lactate was measured while a beat-to-beat heart rate recording was executed during each workout. Cortisol (C) and testosterone (T) were measured in salivary samples.

2h before the workouts the subjects who had to abstain from sexual intercourse, stimulants and alcohol from 2 days before to the experimental days and until 9:00 a.m. of the following day, consumed a standardized meal that was lower to 400 and consisted of 33 cl of water, 35 cl of orange juice and two 30 g energy bars (Power Sport Double Use, Enervit, Milan, Italy).

Lets look at the results

While the protocols elicited the same heart rate response (the major part of each workout was spent between 80 and 100% of maximal heart rate, confirming the high cardiovascular intensity of the workouts), they elicited different hormonal and lactate variations with the LADDER workout producing the lowest lactate increase and the RANDOM workout eliciting the highest lactate, cortisol and testosterone increases.

Figure 1: Relative changes in hormone and lactate concentration in response to the workouts (Di Blasio. 2014)

When C was considered in ratio with T no significant differences have been shown among workouts-induced variations. Results of the analysis of covariance, executed on significantly modified variables, confirmed that basal hormonal and lactate values did not influence their variations.

When they studied the effects of workouts on prolonged hormones production (i.e. until the morning following the morning, di Blasio et. al. found that observed that observed that

"C had both time (F=179.723; p < 0.001) and group × time effect (F=10.942; p < 0.001): while during non-training day there is a physiological decline of C production at 11:00 p.m., during training days its decline is not present but seems to have a continuous increase from 7:00 p.m. to 7:00 a.m." (Di Blasio. 2014)

For the testosterone production the authors found both time (F=443.340; p < 0.001) and group × time effect (F=3.254; p=0.008) even if the group × time effect seems determined by the samples collected at 7:00 p.m., so that the effects cannot be ascribed fully / exclusively to the workout.

Figure 2: 23h hormone profile after the RANDOM, LADDER, ASAP workouts on a control day (di Blasio. 2014)

What is most interesting, though, is the cortisol to testosterone ratio. It shows the greatest inter-group differences and could potentially be of great physiological relevance (Crowley. 1996). In that, the LADDER workout has the most negative effect, as it will totally blunt the natural decline of the C:T ratio at noon.
References:

• Crowley, Michael A., and Kathleen S. Matt. "Hormonal regulation of skeletal muscle hypertrophy in rats: the testosterone to cortisol ratio." European journal of applied physiology and occupational physiology 73.1-2 (1996): 66-72. 
• Schoenfeld, Brad J. "Postexercise hypertrophic adaptations: a reexamination of the hormone hypothesis and its applicability to resistance training program design." The Journal of Strength & Conditioning Research 27.6 (2013): 1720-1730.